Commoditization of display devices has progressed as a result of recent technological innovation. Higher-value-added products are being required and have still been actively developed.
As added value for display devices, a reduction in power consumption has attracted attention for the purpose of extending operation time of a mobile device or the like.
For example, Patent Document 1 discloses a structure of a display device in which the frequency of writing signals (also referred to as refresh) for the same image is decreased to reduce its power consumption in displaying the same image (still image) continuously.
In addition, a change in an image at the refresh should not be noticed by users. Note that refresh frequency is referred to as refresh rate.